sh: unwinder: Fix up invalid PC refetch in dwarf unwinder.

The dwarf unwinder presently attempts to provide a sane PC value if none
is provided, however the logic is broken and cases where a previous valid
dwarf frame exists along with a bogus PC value can still proceed. This
fixes up the test and prevents the unwinder from blowing up.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c
index 2d07084..d76a231 100644 (file)
--- a/arch/sh/kernel/dwarf.c
+++ b/arch/sh/kernel/dwarf.c
@@ -555,7 +555,7 @@ struct dwarf_frame * dwarf_unwind_stack(unsigned long pc,
         * NOTE: the return address is guaranteed to be setup by the
         * time this function makes its first function call.
         */
-       if (!pc && !prev)
+       if (!pc || !prev)
                pc = (unsigned long)current_text_addr();
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER